You’re browsing the applications running using Activity Monitor when you notice something you don’t recognize: nsurlstoraged. What is this, you might be wondering, and why is it using network and CPU resources? First, don’t panic: this is part of macOS.

This particular resource, nsurlstoraged, is a daemon, which means in runs in the background of your system. To be more specific, nsurlstoraged is the daemon in charge of managing local storage for web applications. To quote the man page, which you can find by typing man nsurlstoraged from the Terminal:

nsurlstoraged is a per-user daemon which manages the user’s HTTP storages.

On the modern internet, websites can store some files locally on your computer: it’s part of HTML5. On macOS, nsurlstoraged is the daemon that makes this local storage possible. Safari is the main application that actually uses this capability, but a number of other Apple programs also use it: Mail, Calendar, and iCloud, for example.

If nsurlstoraged is using up a lot of CPU, you might have a corrupt cache. But thankfully, ther’s a quick fix. First, force quit Safari; if nsurlstoraged CPU usage drops you know that Safari is the problem; if not, force quit other applications until you see CPU usage drop.

Justin PotJustin Pot has been writing about technology for over a decade, with work appearing in Digital Trends, The Next Web, Lifehacker, MakeUseOf, and the Zapier Blog. He also runs the Hillsboro Signal, a volunteer-driven local news outlet he founded. Read Full Bio »